Objective: To investigate the clinical significance of combining the Q-switched Nd:YAG laser PTP mode with microneedling using 40% lactic acid in the treatment of melasma. Methods: A total of 40 female patients with melasma (Fitzpatrick type III–V), aged 18–55 years, were enrolled between December 2025 and February 2026. Patients were randomly assigned using a random number table into two groups: 20 patients in the control group (treated with Q-switched Nd:YAG laser PTP mode alone) and 20 patients in the experimental group (treated with Q-switched Nd:YAG laser PTP mode combined with microneedling using 40% lactic acid). Each treatment session lasted 2 weeks, with a total of 8 treatment sessions per patient. Comparative analyses were conducted before and after treatment across all relevant endpoints, including the MASI score and the overall physician evaluation score (PGA). Results: Among the 40 patients, 2 cases were excluded (1 in the control group and 1 in the experimental group), leaving 38 patients for final analysis. After treatment, the MASI scores in both groups significantly decreased compared to baseline values (P<0.001); however, the rate of MASI reduction in the experimental group (54.23±8.61)% was significantly higher than that in the control group (33.17±7.26)%, with a statistically significant difference (t=7.892, P<0.001). VISIA examination revealed that the experimental group exhibited a more pronounced reduction in pigment load; under dermoscopy, the experimental group demonstrated greater dispersion of pigment granules and superior improvement in abnormal capillaries compared to the control group (Z=2.733, P=0.006); the clinical efficacy rate of PGA in the experimental group was 78.95%, significantly higher than that in the control group (42.11%) (Z=2.816, P=0.005). In conclusion, the combination of Q-switched Nd:YAG laser PTP mode and microneedling with 40% lactic acid can enhance patients" subjective satisfaction without increasing the risk of serious adverse reactions.